Viscum album L. Therapy in Oncology: An Update on Current Evidence

A majority of oncological patients apply add-on white-berry European mistletoe (Viscum album L., VA) extracts to reduce disease- and treatment-related symptoms and to improve health-related quality of life (HRQL). VA extracts exert various antitumor, pro-apoptotic, anti-proliferative, and immunomodulatory effects. Two current meta-analyses attribute life-prolonging and HRQL-improving properties to additive VA therapy. The aim of the present update was to review the current knowledge on VA extracts in clinical oncology. Hereby, we concentrated on studies with the highest clinical relevance in the field of lung, gastric, colorectal and pancreatic, gynaecological, as well as breast cancer applying the anthroposophical mistletoe preparations.

The present update provides a brief overview regarding the use of VA preparations in clinical oncology reviewing current guidelines, systematic reviews, randomized controlled and real-world data studies. We have searched the pubmed.gov database of the National Library of Medicine with the search terms "mistletoe" and "cancer." We found good evidence of add-on VA therapy to improve the HRQL of patients with breast cancer (American Society of Clinical Oncology - endorsed Society for Integrative Oncology guideline) and of HRQL-improving and survival-prolonging properties of VA therapy in pancreatic cancer. In the field of gastrointestinal, gynaecological, and lung cancer, new or updating integrative and/or oncological guidelines should consider clear recommendations on integrative therapies including VA therapy. Nevertheless, further clinical and real-world data trials need to be performed in this field.

Evidence for add-on VA treatment for the improved management of cancer and cancer-related side effects is accumulating. Patients with breast cancer: good evidence for add-on VA therapy to improve the HRQL of oncological patients. Patients with pancreatic cancer: good evidence for add-on VA to improve HRQL and prolong survival. Patients with gastrointestinal, gynaecological, and lung cancer: update of guidelines is recommended with regards to integrative oncological therapies including add-on VA.